Shears



(No Model.)

H. T.. SEYMOUR. SHEARS Patented Mar. 27, 1894.

WITNESSES: 1

ATTORNEYAZ 1 Tue NATIONAL umolumuua com-Anvvuwmnrou. n. c;

Elmira 'rATns HENRY T. SEYMOUR, OF NEW YORK, N. Y., ASSIGNOR TO THE HENRY SEYMOUR OUTLERY COMPANY, OF NEW YORK.

SHEARS.

SPECIFICATION forming part of Letters Patent No. 517,244, dated March 27, 1894.

Application filed April 13, 1893. Serial No. 470,166. (No model.)

To 00% whom it may concern.-

Be it known that I, HENRY T. SEYMOUR, a citizen of the United States, and aresident of the city, county, and State of New York, have invented a new and useful Improvement in Shears, of which the following, taken in connection with the accompanying drawings, is a specification.

My invention relates to means for automatically compensating for the wear upon the blades at their pivotal point and for maintaining a constant but yielding pressure upon the blades, and it consists of the construction hereinafter set forth. 7

In the drawings Figure 1 represents a plan view of the shears with the pivotal bolt removed. Fig. 2 is a side view of the shears sectioned on the line was of Fig.1. Fig. 3 is an enlarged detail sectional view representing the relation of the parts before the pivot bolt is fastened firmly in place. Fig. 4 is a similar view showing the relation of the parts after the pivot bolt is fastened and locked in place. Fig. 5 is a perspective view of a spring plate.

The blades A, B of the shears are pivotally connected together by means of a bolt 0 having a screw-threaded shank and a head convexed on its under side. The bolt passes through a smooth-bored perforation a in the blade A of slightly greater diameter than the bolt, and is tapped into a screw-threaded perforation in the blade 13. It is locked in place by the nut E concaved on its wearing surface 6. The perforation a opens on the upper surface of the blade A into an enlarged cavity a having inwardly tapering walls, that is walls tapering so as to make the diameter of the cavity a less at its inner end than at its outer end. Within this cavity, preferably circular in form, rests aspring plate D. This spring plate is preferably concaved along one diameter and is provided with a central perforation, all as clearly shown in Fig. 5. The head of the bolt, which is made smaller than the cavity a, rests upon the upper surface of the spring plate as shown in Fig. 3, and when the bolt is screwed down to place the spring plate is put under tension and the edges are forced up the tapering walls of the cavity until the spring is very nearly flat as shown in Fig. 4. As the blades of the shears wear away from use the edges of the spring plate gradually move down the tapering walls of the cavity and continue to hold the blades under a constant, steady pressure. It will be observed moreover that by my arrangement there is little or no frictional contact between either of the blades and the bolt, and that substantially the only friction upon the bolt comes between the head thereof and the spring plate.

As occasion requires the bolt may be screwed down upon the spring putting it again under tension as explained. Inasmuch as the spring plate always fits snugly against the tapering walls of the cavity, there is no opportunity for the blades to Wabble one on the other whatever may be the wear at their pivotal point.

In the use of the shears the spring gradu ally loses its resiliency, and, after a considerable time in order to get the requisite degree of tension upon the spring and pressure upon the bolt it will be necessary to screw the bolt down until the spring becomes perfectly fiat. This can be readily done and the spring will continue to be effective, as its edges will be forced up the tapering walls of the cavity and the middle portion of the spring be prevented in this way from coming into contact with the bottom of the cavity. From time to time the bolt can be screwed in still farther, the middle of the spring being depressed more and more, and the spring being thus arched in the opposite manner from What it was originally.

The efiective operation of the spring and hence of the shears is thus greatly prolonged by my improvement.

What I claim as new, and desire to secure by Letters Patent, is

l. The combination of a pair of shear blades, one of which is provided with an enlarged cavity with inwardly tapering Walls, a pivot bolt for the blades and a spring plate resting in the enlarged cavity and held under tension by the pivot bolt, substantially as described.

2. The combination of a pair of shear blades, one of which is provided with an enlarged cavity with inwardly tapering walls, a pivot bolt for the blades and a spring plate eoncaved along one diameter resting in the enlarged cavity, all substantially as described.

3. The combination of a pair of shear blades, one of which is provided with an enlarged cavity with inwardly tapering walls, the other of which is provided with a screw threaded perforation, a pivot bolt for the blades having a screw-threaded shank and tapped into the screw-threaded perforation, and a concaved spring plate resting in the enlarged cavity and held under tension by the pivot bolt, substantially as described.

4. The combination of a pair of shear blades, one of which is provided with an en- HENRY T. SEYMOUR.

\Vitnesses:

HENRY D. WILLIAMS, J. P. BROWN. 

